1 Universitat Politècnica de Valéncia, 2 Guy Carpenter

Losses by earthquakes

  • More than US$600 billion in economic damages during the last 20 years
  • 721,000 fatalities
  • Very hard to predict

 

Obstacles and issues related to insurance policies

Results from catastrophe risk model based on Monte-Carlo simulations

More than 100,000 Monte-Carlo simulations are not enough. Large areas uncovered and very few ‘big’ earthquakes.

Interpolating results with Thin Plate Splines

  • Data doesn’t have to be regularly spaced
  • Performs spatial interpolation including covariates (Magnitude, Depth)
  • No knowledge of the functional form of the modeled relationshiop is needed

 

\(y= \beta_{0}+ f(x)+ e\)

 

In R, TPS can be adjusted with the Tps function in the fields package. The level of smoothing for the spline must be optimized by cross-validation.

Interpolating results with Thin Plate Splines

Components of the model:

  • Spatial coordinates
  • Covariates (Magnitude and Depth)
  • Polynomial function for the drift or spatial trend

Results

Results

 

  • Predictions cover all the required area since we are fitting a surface.
  • Prediction error is acceptable and calibration is good.

Conclusions

  • Thin plate splines are a good alternative for complementing the results of catastrophe risk models based on Monte-Carlo simulations

 

  • They can deal with irregularly spaced spatial data and produce smooth estimates over all the studied area.

 

  • In our model for Chile, prediction error and calibration were satisfactory.

 

Future work: Implement a methodology to estimate uncertainty in the predictions –> bootstrap